I have the feeling that the ARW post-processing with Darktable leads to strange results. I tried:
- the "standard" base curve
- Base curve with two or three exposures Fusion 
- Base curve off and instead movie module 
Regardless of what I do, the resulting image I view with "Image Viewer" is much darker (saturated?) And flatter than in DT if I get the desired effect on the screen when converting the file to JPEG.
: See https://www.darktable.org/2016/08/compressing-dynamic-range-with-exposure-fusion/
: See https://www.darktable.org/2018/12/darktable-26/